Phase adjusting apparatus



Aug. 15, 1950 A. G. cooLEY PHASE ADJUSTING APPARATUS Original Filed Oct. 28, 1943 H/435 SH/FTEB OSCILLATOR l5 IN VEN TOR.

A. G. COOLEY A\TTORNEY Patented Aug. 15 1950 PHASE ADJUSTING APPARATUS Austin Gt. flcoley, New York, N. Y-,. assignor to Facsimile Corporation, a corporation of New York Original application October 28, 1943, Serial No.

598,041, new Patent No. 2,411,147, dated N- vemh r 13, use.

Divided and this application August 31, 1946, Serial No. 634,392

This invention relates to phase-adjusting apparatus for alternating-current systems.

The object of the invention is to provide improved control mean for phase-adjustment. of electric currents, to enablev the phase of analternating-current wave to be Varied. through a range of 360 or more. The control apparatus embodying the invention is useful in various systems including remote-control systems of the type disclosed in m prior Patent Number 2,411,147 granted November 19, 1946, which the present application is a division.

Another object of the invention is to provide phase or frequency-adjusting apparatus of this character which may be controlled by a small amount of energy or power input and permit smooth, rapid adjustment over a wide range, if desired.

In describing my invention in detail and to bring out further objects andadvantages theref, reference will be made to the attached drawing illustrating two preferred embodiments of" the invention. In the drawings, Fig: l is a diagrammatic view of a remote-controlsystem employing phase-adjustingapparatus; Figs. 2- and are detail views of a pharse-adiusti-hg-arranga ment employing optical elements;- and Fig; l is a similar view of a modification.

Referring to Fig. l of the drawings, a remoteoontro-l system is illustrated in thisflgure com-- prising two single-phase synchronousmotors it and t2 adapted to be continuously driven byalternatlng currents of two different frequencies transmitted over a control circuit H. An os cillator i5. is shown by way of example as a source of current for operating the motors H- and [2. The oscillator is is connected through a phaseshifting apparatus :6 to a primary winding- H of a transformer [8. The phase-shifter I6 ispro vided with suitable means, such as a manually operable handwheel Zli, for varying the phaserelation between the input and output currents through said phase-shifting device. The oscillater It is also connected through a frequencychanger 22 in order to. impress an alternating current of another constant frequency upon the second primary winding 2-3 of the transformer 58. Thus currents. of two. different. frequencies, one constant and one variable by operation of the phase-shifter it, re induced inthe secondary winding 2d of the. transformer which is connected to. the control circuit: E3.

The frequencies of the currents supplied by the transformer t8. to.- the; control circuit are preferably in, the: audio.- rangebetween a. few:

4 Claims. (Cl. 323-119) hundred and a few thousand cycles, such frcquencies being readily separated at the receiving, end of the system by filters 25 and 26 to operate. the associated synchronous motors at. speeds corresponding to the frequencies of the separate control currents. As indicated, amplifiers 2'1 and 23 may be provided if desired,v between the filters and the respective motors II and I2.

The motors may be of the reluctance or phonicv wheel type similar to that. described in my prior Patent 212,257,153, dated September 30, 19.41. A motor of this type is designed to deliver substantial power when the frequency of the applied current is of the order of one or two thousand. cycles. The frequency of the. oscillator l5 may, for example, be 1800 cycles per second and the: output of the frequency-changer '22 may be a.

constant frequency of I200 cycles per second.

The two motors H and t2 at the receiving sta tion are connected through differential gearing. iii to an index or movable arm 32, the position; of which is to be controlled by adjustment of the:

movable control member 2| at the remote trans-' mitting station. If the motors H and I2 have: the same numbers of poles so that they run at; different speeds, gearing 33 may be provided to drive the differential gearing at the proper speed relation so that the control member 32: will be fixed in position at a predetermined ratio of the control current frequencies in the control cir suit [3. Alternatively, the motors, I l' and it may be constructed with different numbers of poles: and the gearing 33 omitted.

In a system of this character, as explained in my prior patent above referred to, the member 32 may be positioned or moved precisely inac-- cordance with the adjustment of the phaseshifting means it and, the accuracy of control is not affected by variations in the supply voltage. or the resistance, inductance or leakage resistance of the control circuit l3; Considerable power is available at the diflerentially controlled' member, if required, and this power need not betransmittedover the control circuit. The phaseshifting means according to the present invention finds an important application in control systems of this type although it maybe used in other alternating-current systems. 7

A preferred construction of the phase-shitting; means is is illustrated in Figs. 2 and 3-,, this means employing a series of translating devices 35, 35, 37 and 38, show-n as photocells. In this; modification a pivoted disc orvane M having a: series of equally-spaced holes 42 around its; periphery is employedas a light-directing memberto vary the light excitation of the photocells as the disc rotates. The disc 4| is arranged or connected to be turned by a manual or mechanically-operated control element to effect phase ad ustment and only sufficient power is required to overcome the friction of the disc journal or pivot. In the particular embodiment illustrated, a fluctuating light source 44 is arranged to illuminate the photocells 35, 36, 3? and 38 in succession as the disc at is turned. The light source 44 may be a neon glow-discharge or arc-discharge lamp connected to an alternating-current supply circuit of constant frequency such as the oscillator whereby a pulsating light of constant frequency is obtained. The optical system shown including plano-convex lenses 45 and 46 and a light shield 11 is constructed and arranged to cause the beam of light which passes through each hole in the disc 4| to sweep progressively over the photocells one after the other as the discis turned. The lenses and the shield are correlated with the size and spacing of the holes 42 and the location and extent of the cathodes of the photocells to insure that the total output current from the cell or ,cells illuminated at any instant remains substantially constant. As shown, the spacing'of the holes l2 is such that as one hole moves past the edge of the opening in the shield ll, the adjacent hole permits light from the source 24 to strike one of the end cells. Thus the photocells are successively illuminated with pulsating light from the lamp as, always in the sequence 38-3l3635, when the holes in the disc ii traverse the light field in the direction indicated by the arrow, and in the sequence 35'33l 38 for the opposite rotation of the disc Ill. This successive energization of the'photocells 3538 is utilized to obtain a signal wave, the phase of which varies in accordancewith the movement of the disk ll in the following manner.

In accordancewith the invention,v the output currents of the respective cells 35 to 38 are phasecontrolled in a predetermined manner and combined in the primary winding of an output transformer d5. A control voltage is generated in the secondary winding of the transformer ie so that alternating current flows in the. output circuit connected thereto which is shifted in phase as the disc ii is turned. As shown, a conventional two-stageamplifier comprising tubes and 52 is provided for the photocell 35. A similar amplifier 53,5 3 is provided for the photocell 36 except that a condenser 55 is connected in the input circuit of the tube 53 to displace the output current of the amplifier 90 with respect to that of the amplifier 5!, 52. Likewise, the amplifier 56, 5'? for the photocell 3'! includes a coupling transformer 58 so that the output current of the amplifier is displaced 180 with respect to that of the amplifier El, 52; and the amplifier 59, 60 for the photocell 38 is similar to the amplifier 55, 51 except for the condenser 6| arranged to effeet a further phase-adjustment of 90 or a total of 270 with respect to the output current from the first photocell 35. The phase-control arrangement illustrated. is preferred but modified arrangements may be employed which embody similar principles in carrying out the invention.

With this arrangement it will be evident that, as the light beam from the light source it is defiected progressively over the series of photocells,

an. output current is generated in the secondary of the transformer 49 which shifts in phase through 366 for each traverse of the light team across all of the photocells and which is of a frequency corresponding to that of the intermittent or fluctuating light source 44. The output currentis of a'frequency which can be readily amplilied in a vacuum tube amplifier and preferably is between several hundred and several thousand cycles. In particular cases, other frequencies and diiferent circuits may be employed for combining the output currents of the photocells to obtain a phase-shift.

A modified form of phase-shifting means which embodies the invention is illustrated in Fig. 4. As in the first modification described above, this construction is designed to operate on a small torque or operating force, and is arranged to provide a continuous phase-shift in either direction through a range of 360 or more. The phase-shift apparatus shown in Fig. 4 comprises a movable control member 54 in the form of a plate or vane which is integral with or se-. cured to compass or other control element. The movable vane 64 is provided with spaced iron inserts 65 supported for movement along a row of translating devices in the form of stationary electromagnets 65, 61, 68 and 59. The spacing between the inserts 65 is such that as the right-hand edge of one insert is moved to the middle of the core of the magnet 65, the lefthand edge of the next insert lies above the middle of the core of the electromagnet 59, and the width of the insert is substantially equal to the distance between the central axes of adjacent magnet cores so that the magnetic flux induced in the inserts 65 remains constant as the vane 64 is moved (assuming that the electromagnets are of equal strength).

The electromagnets 65, 67, 68 and 69 are connected to an alternating-current supply circuit ll, for example, of a frequency of the order of one or two thousand cycles. However, a condenser ?2 is connected in series with electromagnet 61 to displace the phase of the current traversing its coil Similarly, means such as a transformer T3 and a condenser is is provided to displace the phase of the currents traversing the electromagnets t8 and 69 by and 270, respectively, with reference to the current traversing the electromagnet 66. Consequently it will be apparent that the algebraic sum of the fluxes in the insert 55 opposite the electromagnets is shifted in phase through 360 as the insert is moved from a position approaching the magnet 56 to a position beyond the magnet 69 or vice versa. A stationary magnetizable core 15 opposite the electromagnets 66 to 59 carries a pickup coil F6 in which current of the same frequency as that of the supply circuit H is induced, said current being retarded or advanced in phase 360 as each insert 65 moves past the core 15. The terminals of the pickup coil 16 are connected to the output or utilization circuit, such for example as represented by the primary wind ing I! of the transformer l8 in the remote-con trol system illustrated in Fig. l.

While the two embodiments of the invention have been illustratedto explain the fundamental principles thereof, other modifications will occur to those skilled in the art and may be made without departing from the scope of the invention as defined in the appended claims.

I claim:

1. In an alternating-current system of the characterdescribeda source of alternating current and phase-shifting means connected to said source, said phase-shifting means comprising a light source connected to said alternating-current source to produce a fluctuating light output, photocell means operatively associated with said light source, means including a rotatable lightdirecting member to vary progressively the illumination of the photocell means and means to obtain a variable-phase alternating current from said photocell means.

2. In an alternating-current system of the character described, a source of alternating current and phase-shifting means connected to said source, said phase-shifting means comprising a fluctuating light source, a series of photocells arranged side by side, a movable light-directing member between said light source and said photocells arranged to vary progressively and in predetermined sequence the illumination of the respective photocells and means in circuit with said photccells for deriving an alternating current the phase of which is dependent on the position of said movable member, said last-mentioned means including separate amplifiers for said photocells each having different phase-shifting characteristics.

3. In an alternating-current system of the character described, a source of alternating current and phase-shifting means connected to said source, said phase-shifting means comprising cyclically varying light-generating means, a series of photocells operatively associated therewith, a movable light controlling vane between said light-generating means and said cells and arranged to eifect progressive and cyclical illumination of different ones of the cells as the vane moves, an output circuit and separate circuits of dififerent phase-shift characteristics connected between each of said photocells and the output circuit to cause the phase of the current in said output circuit to depend upon the particular cell which is operative.

4. Phase-shifting apparatus comprising a plurality of circuits of differing phase-shift characteristics, a common output circuit connected to said other circuits and light-sensitive means for energizing any of said first-mentioned circuits, to produce a current flow in the output circuit of corresponding phase.

AUSTIN G. COOLEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,655,040 Alexanderson Jan. 3, 1928 1,667,497 Shapiro Apr. 24, 1928 1,832,707 Hull Nov. 17, 1931 2,085,940 Armstrong July 6, 1937 2,228,078 Gulliksen Jan. 7, 1941 2,261,083 Harrison Oct. 28, 1941 2,288,740 Peterson July 7, 1942 2,411,030 Ryder Nov. 12, 1946 

